You may already have a boatload of nutrients in your fields. They’re in the form of crop residue and beneficial microorganisms. Corn stover, for example, has on average 17 pounds of N, 4 pounds of P, 34 pounds of K, and around 3 pounds of S per ton of dry matter. (1) Those are your macronutrients sitting there in the field, if you haven’t disced them in.
What Happens to Crop Residue Nutrients After Discing?
After discing, microorganisms feast. Cultivated soils, most of our ag cropland, are bacterial dominant. That bacterial dominance means you have gaps in your microbial populations and that’s where pathogens creep in. They too feast on crop residue. For an in-depth dive into microbes and crop residue, go here.
How Do You Maintain Fertility With Fewer Inputs?
A fertile field has a great deal of fungal microorganisms, as well as nematodes, protozoa, and bacteria, in balance. The vast majority of microorganisms are beneficial. Pathogens can take over when there is a gap in the microbial population. Fungi don’t do well in a tilled field. Discing activity cuts the hyphae off the fungi that supply plants with nutrients and water. If you’ve heard the term cut off your nose to spite your face, well, that’s what you’re doing when you till a field. But tilling keeps down weeds and creates a nice seed bed, you’re about to say.
Let’s talk about that. The history of agriculture is littered with conflicting opinions on tillage as a best practice. Most commodity crop growers today would say tillage is necessary, but they are discounting the benefits of soil cover and those microbes.
The NRCS developed the STIR (Soil Tillage Intensity Rating) to evaluate the effects of tillage on cropland. According to the NRCS:
“Low STIR values reduce the likelihood of sheet and rill and wind erosion. Other benefits of low STIR values include increasing Organic Matter (OM) content of the soil, less OM breakdown, lower carbon losses from soil to the atmosphere, improved soil consolidation conditions, and greatly improved infiltration rates.” (2)
In other words, the less you till, the fewer input you have to add. Isn’t that a great way to keep nutrients cycling with happy fungi and other microorganisms, increase soil carbon, and create resilience in your fields? Extra bonus: it costs you less money and time.
What Nutrient Sources Work Best for Your Ag Operation?
We tend to think of fertilizing when we plant. But when does a plant actually need fertilizer? A seed comes with its own nutrient reserve. If the soil is alive with microorganisms and high in organic matter, you won’t need fertilizer until later in the growing cycle. Corn, for example, doesn’t need nitrogen until V6 and then again perhaps at V10–12 and R1.
What form of fertilizer works best at these stages? Foliar sprays are absorbed rapidly by plants, increasing metabolic activity. Nutrient molecules can get tied up in the soil when they bond with other molecules. The electrical charges of cations and anions are always creating new compounds in the soil or in the plant. Measuring the nutrients in soil isn’t necessarily an indication of what nutrients are in the plant.
Liquid forms of fertilizer are easier for a plant to absorb through the stomata and cell membranes. Foliar feeding puts more nutrients directly in the plant and less to leach away in the soil. They can be in the form of a solution, colloid, emulsion, or a true solution. Plants uptake both macro and micronutrients in specific chemical forms. And because microbes are everywhere, the microbiome on the plant leaves helps convert any nutrient inputs into the optimum food for plant growth.
It matters what stage a plant is at when you’re applying nutrients. Corn needs the micronutrient manganese in early growth stages to prevent deficiencies later and to affect chlorophyll production. A foliar application is the most effective.
If one of your goals is a healthy and vigorous crop, which will result in a higher yield, think in terms of plant and soil health. It’s easier for a healthy plant and a robust microbial population in the soil to fend off diseases and pests, and 1–2 percent of microorganisms that are pathogenic.
Healthy plants and beneficial microbes fend pathogens off. Pathogens can’t reach economic levels when there aren’t enough of them. And if beneficial microbes are taking up the real estate around plant roots (the rhizosphere), then there’s nowhere for pathogens to feast. The goal isn’t to totally eradicate pathogens but to get them under control. When you enlist the aid of microorganisms and feed your crops the nutrients they need, you’ll be surprised at the outcome.
To find out more about the powers of biologicals and regenerative ag practices, contact our team at ST Biologicals. We’re here to help you succeed. When soil speaks, we listen.
